Lodger's boyfriend moving in for short period

Hi

I have a lodger in my house who is paying 430 a month for a large room, all bills included. That's fine and she's fine. She's an Erasmus student but wanted to stay on for the summer to explore Ireland, and she did tell me the plan was for the boyfriend to come over for the summer holidays. So it save me having to find someone for the summer. Now I need to come up with a fair figure to add to the rent and was wondering would 150 per month be too much? That's 37.50 per week, for the extra utilities and the inconvenience of having an extra person around. The house is in Dublin, it's a large enough 4 bedroom house inside the canal on the south side, on a Luas line.

any opinions?
Thanks

That's more than fair, I would charge a tenner a night minimum, and get a passport photocopy.
We get 25 per day for our students in summer ,that includes breakfast and evening meal .

Thanks GDUFFY, I'm not providing any food, she has her own fridge and looks after her own catering. It's just utilities that are included in the rent.

I'd round it up to €600 per month, €300 a month for a place to stay where you're free to do your own thing is a bargain. I'd make sure to set the ground rules so that there's no confusion.

what becky said. Also be aware that the 'dynamic' changes considerably in a house share where there's a couple involved. Be aware of that as a potential problem.